Engine torque: Diagnostics

In the event of a malfunction, a diagnostic trouble code will be generated primarily in the Trionic system.

When bus communication with Trionic ceases, diagnostic trouble code P1921 will be generated and the transmission goes into Limp-home mode.

Inaccurate information on the bus causes diagnostic trouble code P1971 to be generated. Depending on the fault, the TCM may activate the emergency operation program (Limp-Home mode).

Fig 1: Engine Torque Communication Flow Circuit Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.